Metal matrix composites. Anne Mertens

Transcription

1 "MECA0139-1: Techniques "MECA additives : et Materials 3D printing", Selection", ULg, 21/11/ /10/2016 Metal matrix composites Anne Mertens

2 Outline Introduction: why composite materials? Case study I: Material for electronic packaging Case study II: Enhanced wear resistance Case study III: Functional materials Processing metal matrix composites: a problem of interface engineering! Summary 2

3 Introduction Why composite materials

4 Why composite materials? To fill gapsin material-property space To obtain combination of properties not available with "simple" materials [M.F. Ashby, Materials selection in mechanical design] 4

5 Why composite materials? New combination of interesting mechanical properties Improved stiffness compared to conventional Al alloys [M.F. Ashby, Materials selection in mechanical design] 5

6 Why composite materials? New combination of interesting mechanical properties Improved stiffness compared to conventional Al alloys Choice of materials? Be is stiffer and lighter than Al Al 2 O 3 is stiffer but heavier than Al [M.F. Ashby, Materials selection in mechanical design] 6

7 Why composite materials? New combination of interesting mechanical properties Improved stiffness compared to conventional Al alloys Configuration? [M.F. Ashby, Materials selection in mechanical design] 7

8 Why composite materials? One can be imaginative! Combine high thermal conductivity and low thermal expansion Enhance wear resistance Design functional materials... Self-lubricating Self-cleaning Self-healing 8

9 Outline Introduction: why composite materials? Case study I: Material for electronic packaging Case study II: Enhanced wear resistance Case study III: Functional materials Processing metal matrix composites: a problem of interface engineering! Summary 9

10 Case study I Material for electronic packaging

11 Electronic pacakging and heat sink [Wikipedia: Fir0002/Flagstaffotos] 11

12 Electronic packaging Thermal expansion α close to α silicon High thermal conductivity (λ) For portable applications: low density (ρ) [S.Ryelandt et al., Euromat 2005] 12

13 Materials for electronic packaging Thermal expansion αclose to α silicon SiC High thermal conductivity (λ) Al For portable applications: low density (ρ) Al Al-SiC composites? [S.Ryelandt et al., Euromat 2005] 13

14 Materials for electronic packaging Al + SiC particulates... but SiC is very brittle! [Huber et al., Comp. Sci. Technol. 2006; Chu et al., Mater. Des. 2009] 14

15 Materials for electronic packaging Al + another metallic material with low α? Invar (Fe-Ni or Fe-Co-Cr alloys) [ [Borvan53 (Own work) [Public domain], via Wikimedia Commons] 15

16 Anisotropy is desirable! Thermal expansion αclose to α silicon (in plane) High thermal conductivity (λ) (in transverse direction) For portable applications: low density (ρ) [S.Ryelandt et al., Euromat 2005] 16

17 Anisotropic Al-invar composite Invar (Fe-Co-Cr alloys) Al Al -20 % stainless invar Thermal expansion αclose to α silicon (in plane) High thermal conductivity: λ= 206 Wm -1 K -1 (in transverse direction) Low density (ρ) [Ryelandt, Mertens & Delannay, Mater. Des. 2015] 17

18 Anisotropic Al-invar composite Invar (Fe-Co-Cr alloys) Al Al -20 % stainless invar Thermal expansion αclose to α silicon (in plane) High thermal conductivity: λ= 206 Wm -1 K -1 (in transverse direction) Low density (ρ) Change α, λand ρby adjusting the volume fraction of invar [Ryelandt, Mertens & Delannay, Mater. Des. 2015] 18

19 Al-invar composites [Ryelandt, Mertens & Delannay, Mater. Des. 2015] 19

20 Outline Introduction: why composite materials? Case study I: Material for electronic packaging Case study II: Enhanced wear resistance Case study III: Functional materials Processing metal matrix composites: a problem of interface engineering! Summary 20

21 Case study II Enhanced wear resistance

22 Ni+SiC composite coatings Electro-deposition of Ni + (nano-particles) of SiC Ni Ni + SiC Composite coating gives better coverage [Lekka et al., Electrochim. Acta 2005] 22

23 Ni+SiC composite coatings Electro-deposition of Ni + (nano-particles) of SiC [Lekka et al., Surf. Coat. Technol. 2012] Hardness [ 23

24 Ni+SiC composite coatings Electro-deposition of Ni + (nano-particles) of SiC Room Temperature At 300 C Resistance to wear [Lekka et al., Surf. Coat. Technol. 2012] 24

25 Ni+SiC composite coatings Electro-deposition of Ni + (nano-particles) of SiC Nano-particles Micro-particles Resistance to scratch [Narasimman et al., Wear 2012] 25

26 Outline Introduction: why composite materials? Case study I: Material for electronic packaging Case study II: Enhanced wear resistance Case study III: Functional materials Processing metal matrix composites: a problem of interface engineering! Summary 26

27 Case study III Functional materials

28 Self-cleaning materials Electro-deposition of Ni + nano-particles of TiO 2 Under UV light, TiO 2 causes photocatalytic degradation of pollutants Efficiency of "selfcleaning" depends volume fraction of TiO 2 structure of Ni matrix [Spanou et al., Electrochim. Acta 2013] 28

29 Self-lubricating materials Lubrication is important in decreasing friction and wear e.g. during machining or sliding contact At high temperature, conventional liquid lubricants (oil,...) do not work Dry lubricants that are stable at high temperatures offer alternatives graphite boron nitride (BN) molybdenum di-sulfide (MoS 2 ) 29

30 Self-lubricating materials Dry lubricants are included in the bearing material (stainless steel 316L) and then released progressively Friction may [Mahathanabodee et al., Wear 2014] 30

31 Self-lubricating materials Dry lubricants are included in the bearing material (stainless steel 316L) and then released progressively Friction may (here with BN additions) [Mahathanabodee et al., Wear 2014] 31

32 Self-healing materials Healing agents/capsules (e.g. with low temperature) are dispersed in the material After service, the material is heat treated to release the healing agent where it is needed [Ferguson et al., JOM 2014] Self healing developed 1st for polymers Very early stage for metals! 32

33 Outline Introduction: why composite materials? Case study I: Material for electronic packaging Case study II: Enhanced wear resistance Case study III: Functional materials Processing metal matrix composites: a problem of interface engineering! Summary 33

34 Processing of MMCs A problem of interface engineering!

35 Role of interface! When using composites, designers generally make the assumption of fully dense, strongly bonded composites Optimal load-transfer between matrix and reinforcement [M.F. Ashby, Materials selection in mechanical design] 35

36 Processing?... but obtaining fully dense, strongly bonded composites is not trivial! Especially by liquid (molten) state processing [K.U. Kainer, Basics of metal matrix composites, 2006] 36

37 Processing must be optimized! Interfacial reactions between matrix and reinforcement may degrade the reinforcement result in undesirable (brittle) reaction products Mg + Al 2 O 3 fibres [K.U. Kainer, Basics of metal matrix composites, 2006] 37

38 Summary Composites allow to fill gaps in the material-property space and obtain new combination of properties enhance mechanical properties (stiffness, wear resistance...) obtain specific combination of thermophysic properties e.g.: material for electronic packaging Functional materials (self-cleaning, self-lubricating, selfhealing...) Warning: processing must be optimized to guarantee the desired properties in metal matrix composites, quality of interface may be affected by reactions between the matrix and reinforcement 38